1. Field of the Invention
The present invention relates in general to the field of telephony information storage and retrieval. More particularly, the present invention relates to processing of telephone caller identification information while the computer is in a powered-down mode.
2. Description of Related Art
As personal computers (PCs) increase in computing power, many applications that are traditionally performed by specialized equipment now can be supported by the PC. Examples of these applications include the provision of facsimile services, telephony services, teleconferencing, video conferencing, and banking.
One of the telephony services that may be supported by the PC is retrieval of Caller-Identification (Caller-ID) information. Caller-ID is a service provided by telephone companies to allow the recipient of a telephone call to retrieve identification information regarding the caller, such as the caller's telephone number. Such Caller-ID signaling is issued by the switching equipment of the telephone company only once, immediately before or after a first ring indicative of an incoming call. To avoid missing the Caller-ID signal, the receiving end equipment such as a PC or a PC that is attached to existing telephony devices, must be powered up and ready to receive and process the information.
A PC is typically interfaced with telephony devices through an external or an internal modem. However, in conventional computers, the microprocessor and its associated peripheral devices (such as the communication serial interface and memory devices) must be powered up and in an active, operational state at the time the call comes in order to capture the caller-ID information.
The continuous maintenance of a PC in powered-on state is impractical due to the associated energy costs involved. In particular, high performance microprocessors such as the Intel Pentium.RTM. microprocessor, have a high power consumption. In addition, there is a trend towards the implementation of increased memory and mass storage in a typical PC. For example, it is not unusual to have a PC populated with 32 MBytes of RAM and more than 1 Gbyte of mass storage. Together with the implementation of other peripheral devices such as a Compact Disc-Read Only Memory (CD-ROM) drive, a high density floppy drive and multimedia devices, a typical PC usually consumes power in excess of 200 Watts.
To conserve power and/or to reduce power consumption, a flexible power management scheme has been developed which switches the PC to a powered-down mode, or sleep state, when there is an indication of user inactivity. The PC may subsequently be awaken or powered-on by automatic detection of some activity such as depression of a key, or by flipping a sleep release switch.
In PCs implementing such power management schemes, retrieval of the Caller-ID information through the modem is unsuccessful because the time it takes to activate the PC is normally longer than the time interval between the start of the first ring, or the alert tone (in European countries), and the issuance of the Caller-ID signal. As a result, the Caller-ID information is typically lost.
Accordingly, there is a need in the technology for an apparatus and method for capturing, storing and retrieving Caller-ID information in a PC while the PC is in a powered-down or sleep state or is transitioning from a powered-down state to an operational state.